1. Field of the Invention:
The present invention relates to a refrigerator system for a container.
2. Description of the Prior Art:
A known refrigerator system for a container in the prior art is illustrated in block diagram form in FIG. 4, and an arrangement of the same system within a container is shown in FIG. 5. In these figures, reference numeral 1 designates a container or enclosed space, numeral 2 designates a compressor, numeral 3 designates a condenser, numeral 4 designates an electronic expansion valve, numeral 5 designates an evaporator, numeral 6 designates a hot gas modulating valve, numeral 7 designates a condenser fan, numeral 8 designates an evaporator fan, numeral 9 designates a container outside temperature detector, numeral 10 designates a container inside temperature detector, numeral 11 designates an electric heater, and numeral 12 designates a controller. Solid line arrows in FIG. 4 indicate the direction of flow of a coolant, and dotted line arrows indicate the direction of flow of air.
In the above-described system, a coolant compressed by the compressor 2 enters the condensor 3, where it is cooled by heat-exchange with air caused to flow by the condenser fan 7, and becomes a high-pressure liquid coolant. The coolant is reduced in pressure in the electronic expansion valve 4, and then enters the evaporator 5, where it is heated by heat-exchange with air caused to flow by the evaporator fan 8, and it becomes a low-pressure gas coolant and returns to the compressor 2. The above-mentioned is a basic operation of a refrigerating system, and in this system the controller 12 compares the temperature detected by the temperature detector 10 within the container 1 with a preset temperature within the container 1, and according to the results of such comparison it performs adjustment of an extent of opening of the hot gas modulating valve 6, ON-OFF switching of the electric heater 11 or adjustment of an extent of opening of the electronic expansion valve 4, and thereby serves to maintain the temperature within the container 1 constant.
However, in the case where the container 1 has superannuated or has been damaged or defective due to any cause, the thermal insulation property of the container is degraded, resulting in large leakage of heat, and a preset temperature within the container cannot be attained, so that a wrong or abnormal condition for the load in the container is produced. Also, even if the preset temperature within the container were to be attained, there would occur a wrong condition in that it takes a long time until the set temperature is attained or a heavy load is applied to the refrigerating system. Moreover, when such a wrong condition had occurred, in the prior art it was not known whether the problem involved the refrigerator system or the problem involved the container.